The present invention broadly relates to conveying machines of the general type for automatically conveying work pieces through a preselected treating cycle. More particularly, the present invention is directed to an automatic conveying machine of the so-called side arm type incorporating a plurality of work carriers including a vertically movable carriage on which a laterally extending supporting arm is affixed to which one or a plurality of work pieces are suspended and are conveyed thereby through successive treating stations in an ordered preselected sequence.
Arm-type conveying machines of the aforementioned type are generally disclosed in U.S. Pat. Nos. 2,945,579; 3,311,214; 3,331,518; 3,504,812; 3,674,127; 3,760,927 and 3,770,150. Conveying apparatuses of the type disclosed in the aforementioned patents are particularly applicable for conveying workpieces or work racks incorporating work pieces thereon through a sequential chemical, electrochemical, electroplating, and the like process in which the work pieces are subjected to a prescribed treatment at each of a plurality of treating stations. The work pieces are adapted to be lowered into appropriate treating fluids at a treating station and are periodically elevated in order that they can be transferred over the partitions separating adjacent treating stations.
The innovation of new treating processes and techniques frequently requires the work pieces to be positioned at an intermediate elevation between the fully raised and fully lowered position. Additionally, variations in the treatment cycle to which selected work pieces are to be subjected further requires a provision for a delayed dip or early pick-up operation as well as a skip operation at certain treating stations to vary the time of treatment of such selected work pieces at such stations. Various mechanisms have heretofore been used or proposed for effecting variations in the treatment time of work pieces at selected work stations which have not been entirely satisfactory for one or a number of reasons. More particularly, arm-type conveying machines of the types heretofore known have not been adaptable for positioning the work supporting arm at one or a plurality of intermediate positions between the fully raised and fully lowered positions. Accordingly, the capability of computerized control systems to provide for sophisticated treating sequences in accordance with the latest technology have not been fully realized in prior art machines.
The conveying apparatus of the present invention comprises an improvement over prior art conveying machines of similar type substantially enhancing the flexibility and versatility of feasible treating cycles to which the work pieces can be subjected.